1. Field of the Invention
The present invention relates to a method and apparatus for deploying a work object and, more particularly, to such a method and apparatus which are particularly well suited to the installation and operation of irrigation systems and the like.
2. Description of the Prior Art
The installation and operation of utility systems of various types present complex problems which may not initially be recognized. For example, the installation and operation of electric lighting systems, sprinkler systems, irrigation systems and other utility systems, particularly such as used in landscaping, present a multitude of difficulties not immediately apparent to people without firsthand experience.
Taking sprinkler and irrigation systems as an illustrative example, the installation of such systems requires careful planning, substantial expense for the required materials and inordinate physical labor in the installation thereof. Where such installation is performed by hired personnel, there is a concomitant expense for these services. While, in large part, metal conduit, risers, valves and sprinklers have been replaced by components manufactured from synthetic plastic materials, this evolution has not alleviated most of the problems associated with the installation of such systems. It is true that components fabricated from plastic are generally cheaper to manufacture, less expensive to the end user, easier to install and otherwise more trouble free than their metal counter parts. It is also true that the use of such plastic components eases the task of replacing broken or worn components, as well as that of modifying such systems once installed.
Nonetheless, the installation of sprinkler and irrigation systems, whether fabricated from metal or plastic, is a highly labor intensive process which has experienced little significant improvement. Typically, such systems, whether metal or plastic, are installed in accordance with the same method. A manifold valve system is assembled and connected to a source of water under pressure at a location relative to the landscaping which is both convenient and, preferably, centralized relative to the landscape area to be serviced by the system. The landscape area is then excavated to form an array of trenches extending throughout the area for the dispersion of water through the system and in accordance with the water requirements of the plant life to be grown therein. This array of trenches is formed either in a single step after which the system is installed therein, or in sequence such as by excavating a trench and then installing the portion of the irrigation system therewithin before proceeding to the next trench.
This excavation process is both tedious and otherwise onerous, even with the use of mechanized equipment. The trenches need to be deep enough that the conduit to be buried therein will not work itself free of the trench over time. There may be other utility systems such as gas lines, other water lines, or buried electrical systems which must be avoided. Similarly, the geological condition of the earth within the landscape area may not be conducive to such excavation. Any combination of rock formation may be present in the earth through which trenching is very difficult, if not impossible. Frequently layers of hard subsoil or clay known as "hardpan" or "caliche", may be present in the landscape area. Where such conditions are present, it may be necessary to soak the subsoil with water, perhaps with the assistance of a suitable penetrant, in order to dig the trenches, even with mechanized equipment. Existing trees, shrubs and other plant life may be supported by well developed root systems which intrude into the areas through which the trenches are to extend. Still further, there may also be virtually any type of waste materials buried in the paths of the trenches including such unpleasant discoveries as broken concrete, plumbing, wood, and the like, from preexisting structures.
Once excavation of the trenches has been achieved, conventional practice calls for the plastic components of the irrigation system to be assembled using a suitable plastic adhesive and extending from the valve manifold to the individual locations at which the sprinklers, or other irrigation devices, are to be emplaced. This process is not itself particularly difficult, but suffers from several rather common difficulties. Particularly where mechanized equipment is used in forming the trenches, it is frequently the case that the trenches do not extend to precisely the positions or depths desired requiting that the trenches be modified to some degree for proper placement of the irrigation devices. The adhesive used in interconnecting the plastic components has a tendency to leak or be forced into the interior of the conduits and, upon pressurization of the system, to be pulled free to be carried along the system resulting in the obstruction of lines and irrigation devices. Such obstructions may be evident when an irrigation device does not operate properly, or when fluid pressure along a conduit is insufficient. However, location of the obstruction may be very difficult where the obstruction is not within the irrigation device itself. This may require that the conduit be replaced. Where the obstruction is within the irrigation device, it may be very difficult or impossible to remove the adhesive from small fluid passages or the orifice thereof. Furthermore, the hardened adhesive may not pull free until a considerable period of time after installation of the system so that the existence of an obstruction does not become apparent until plant life watered by the irrigation device languishes. Compounding these problems is the all too human tendency of those responsible for such installations simply to ignore these problems resulting in an irrigation system which is defective to one degree or another.
Once an irrigation system has been installed, there is a continuing need for maintenance in order to ensure that the system function properly. Conduits and irrigation devices may become obstructed through a long period of use due to a wide variety of causes. Portions of the irrigation system may need to be repositioned, extended, shortened, replaced, or otherwise modified in order satisfactorily to irrigate plant life in the landscaped area. Irrigation devices may be damaged or broken off by passersby, lawn mowers and the like. Similarly, portions of the conduit may inadvertently be punctured, fractured or may otherwise require replacement. Where these needs arise, all of the problems associated with installation previously cataloged are again presented.
Still another circumstance inherent in conventional sprinkler and irrigation systems and methods for their installation is the need to have the irrigation devices and, depending upon the type, the risers thereof, exposed to view throughout the landscape area. Those irrigation devices which are operable to water larger plants are typically permanently mounted on elevated risers. Furthermore, certain plants such as ferns, require the foliage to be topically sprayed in addition to irrigation of the root zone. These facts result in two primary problems. A first problem is that the presence of such equipment detracts from the overall aesthetic appearance of the landscaping. While landscape plans frequently attempt to take into account such considerations by placing sprinklers behind plants, to the extent possible, so as to disguise their presence, the utilitarian need to irrigate the plant life requires a degree of exposure. Secondly, the exposure of such irrigation equipment virtually ensures that it will be damaged over time due to impact by passersby and by equipment, such as lawn mowers. Thus, those responsible for continued operation of the irrigation system must be observant for such damage and must make the repairs on those occasions as required to keep the system in operation. Such maintenance is a more or less continuous problem for those responsible.
The use of plastics in the manufacture of such components increases the risk of such damage as compared with metal components. However, the use of metal risers and metal sprinklers on systems which are otherwise plastic, is not necessarily more resistant to damage. For example, the metal risers are not themselves flexible and so any impact applied thereto is transferred to the plastic conduit beneath, resulting frequently in the buried conduit being fractured and requiring, perhaps, even more effort to repair the damage.
Therefore, it has long been known that it would be desirable to have a method and apparatus for deploying a work object which is particularly well suited to usage in the installation and operation of such utility systems as subsurface electrical systems, sprinkler systems and other irrigation systems; which permits such utility systems to be installed rapidly, dependably, and at a cost significantly below that which is heretofore been possible; which can readily be modified or otherwise adjusted with little or no difficulty particularly when compared with conventional methods and apparatuses; which require significantly less labor in the installation process than has heretofore been possible; which, once installed, is essentially invisible when not in operation; which, upon operation, deploy the operable portions thereof in the optimum positions; which can readily be adjusted to accommodate growth in plant life over a long operational life; and which otherwise are entirely successful in accomplishing their operational objectives.